Smart environments represent the next evolutionary development step in building, utilities, industrial, home, shipboard, and transportation systems automation. Like any sentient organism, the smart environment relies first and foremost on sensory data from the real world. Sensory data comes from multiple sensors of different modalities in distributed locations. The smart environment needs information about its surroundings as well as about its internal workings.
One of the important sensors which can be used for smart environment is image sensor. Image sensors are used primarily in digital cameras and in a large number of imaging devices used in industrial, media, medical, and consumer applications. Image sensors are standard measurement tools to convert light to digital signal to be processed by a control processor.
There are two image sensors that dominate digital photography today: CCD (charge-coupled device) and CMOS (complementary metal-oxide semiconductor). Each image sensor has its place in the world but comes with very distinct advantages and disadvantages.
Both CCD and CMOS image sensors start at the same point—they have to convert light into electrons. It is somehow similar to how solar cells work. One simplified way to think about the image sensor is to think of it as having a 2-D array of thousands or millions of tiny solar cells, each of which transforms the light from one small portion of the image into electrons
Image sensors by definition convert electrons into voltage. However, there are different ways to get from point A to point B. A CMOS sensor has circuitry at every photo sensor. So each pixel is read simultaneously and then transmitted as digital information at once. This set up leaves the chip relatively crowded with circuitry but is extremely efficient and fast. In a CCD imager, the pixels are recorded on the chip and then one by one sent through the analog to digital converter to build the data. This takes more power than the CMOS process, but delivers much cleaner images.
CMOS sensors generally record less resolution than CCD sensors because they cannot physically sustain as many pixels on the plane of the chip. Each CMOS pixel is packaged with the circuitry to convert it to a digital signal, thus each sensor takes up more space.
CCD sensors tend to respond better to low light conditions than CMOS sensors. The clutter on CMOS sensors reduces the light sensitivity of the chip. It takes more lights to penetrate the thick layers, so dim light will not make it through. However, the advantage is that CMOS sensors facilitate adding gain to an image. Because circuitry is so close to each pixel, the camera can boost the exposure as it is recorded.
Wireless sensors are also used in smart environment. They are equipped with transmitters to convert signals from a control processor into a radio transmission. Then the reflected radio signal is interpreted by a receiver which then detects the received signal and sends it to a processor to be analyzed.
This patent application discloses use of image sensors for body protection gears. The image sensor is applied to estimate and calculate the distance and approaching speed of an external object, and use this information to decide to activate functions or devices that protect the body. This application also discloses use of both wireless sensor and image sensor for body protection.
The drawings referred to in this description should be understood as not being drawn to scale except if specifically noted.